• Title/Summary/Keyword: Systematic errors

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Predicting Human Errors in Landing Situations of Aircraft by Using SHERPA (SHERPA기법을 이용한 항공기 착륙상황에서 발생 가능한 인적오류 예측)

  • Choi, Jae-Rim;Han, Hyeok Jae;Ham, Dong-Han
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.29 no.2
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    • pp.14-24
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    • 2021
  • This study aims to examine probable human errors when landing an airplane by the use of SHERPA(systematic human error reduction and prediction approach) and propose methods for preventing the predictive human errors. It has been reported that human errors are concerned with a lot of accidents or incidents of an airplane. It is significant to predict presumable human errors, particularly in the operation mode of human-automation interaction, and attempt to reduce the likelihood of predicted human error. By referring to task procedures and interviewing domain experts, we analyzed airplane landing task by using HTA(hierarchical task analysis) method. In total, 6 sub-tasks and 19 operations were identified from the task analysis. SHERPA method was used for predicting probable human error types for each task. As a result, we identified 31 human errors and predicted their occurrence probability and criticality. Based on them, we suggested a set of methods for minimizing the probability of the predicted human errors. From this study, it can be said that SHERPA can be effectively used for predicting probable human error types in the context of human-automation interaction needed for navigating an airplane.

A Study on Precision Rectification Technique of Multi-scale Satellite Images Data for Change Detection (변화탐지를 위한 인공위성영상자료의 정밀보정에 관한 연구)

  • 윤희천;이성순
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.22 no.1
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    • pp.81-90
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    • 2004
  • Because satellite images include geometry distortions according to photographing conditions and sensor property, and their spatial and radiational resolution and spectrum resolution are different, it is so difficult to make a precise results of analysis. For comparing more than two images, the precise geometric corrections should be preceded because it necessary to eliminate systematic errors due to basic sensor information difference and non-systematic errors due to topographical undulations. In this study, we did sensor modeling using satellite sensor information to make a basic map of change detection for artificial topography. We eliminated the systematic errors which can be occurred in photographing conditions using GCP and DEM data. The Kompsat EOC images relief could be reduced by precise rectification method. Classifying images which was used for change detections by city and forest zone, the accuracy of the matching results are increased by 10% and the positioning accuracies also increased. The result of change detection using basic map could be used for basic data fur GIS application and topographical renovation.

Development of accuracy for the statical inclinometer by error analysis (다축 수준기의 오차분석을 통한 측정 정밀도 향상)

  • Lee J.K.;Park J.J.;Cho N.G.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.1797-1802
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    • 2005
  • In this study, we were developed an accuracy of the proposed two dimensional statical inclinometer what used a position sensitive detector(PSD) by an error analysis. The inclinometer consists of a laser source, a mass, an optic-fiber, and a PSD. The gravity direction on a base platform of the inclinometer is changed by an unknown inclination angle. And a laser spot is moved from the origin to another position of a PSD following a variation of an optical path by the gravity. These processes enable the inclinometer to estimate the inclination angle from distance information of the moving spot. A design methodology on the basis of a sensitivity analysis was applied to improve the measurement performance such as a full measuring range and a resolution. But it still has error factors, so we analyze the uncertainty of the inclinometer to evaluate the systematic errors from alignments, assembly error and so on. The experimental performance evaluation about the design objectives as a measuring range and a resolution was performed. And the validity and the feasibility of the design process were certified by an experimental process. Systematic errors eliminated to improve the accuracy of the inclinometer by the corrected measuring model from the calibration process between the inclination angle and the PSD position instead of the nominal measuring model. The ANOVA(analysis of variance) confirmed the effect of eliminating the systematic errors in the inclinometer. From these methodologies, the proposed inclinometer was able to measure with a high resolution(35.14sec) and a wide range(from $-15^{\circ}\;to\;15^{\circ}$

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Improvement of Accuracy for Determination of Hydrogen Storage of Sieverts Apparatus (부피법을 이용한 수소 저장 성능 평가 장치의 수소 저장량 측정법 개선)

  • Cho, Won-Chul;Han, Sang-Sub;Park, Chu-Sik
    • Transactions of the Korean hydrogen and new energy society
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    • v.19 no.1
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    • pp.64-70
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    • 2008
  • This paper briefly discusses the main sources of errors and their solutions for measuring hydrogen uptake from gas phase by the Sieverts technique. Correction of volumetric errors of apparatus, density of hydrogen storage material, estimation of temperature gradient are investigated. Systematic errors and the change of density of the host material according to the pressure have been the subject of much controversy in recent years. We considered the standard ball calibration, temperature gradient distribution, pretreatment of hydrogen storage materials to minimize errors. We could lessen the miscalculations after applying those methods to Equilibrium pressure-composition isotherm data.

Task Types and Loads of Railway Worker (열차운용원의 직무유형 및 직무부하)

  • Han, Kyu-Min;Ko, Jong-Hyun;Jung, Won-Dea;Kang, Jung-Seok
    • Proceedings of the KSR Conference
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    • 2007.05a
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    • pp.1204-1208
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    • 2007
  • In order to prevent railway accidents due to human errors which have been recognized to be the most important cause in the railway accidents, human errors should have been controlled based on systematical analysis of the human errors, and countermeasures should be derived to reduce human error probability. Among several factors inducing human errors, task load (or task complexity) is representative. In order to reduce the human error, a systematic analysis should be undertaken to evaluate task load. In this study, task load according to task types of railway worker who are a safety critical staff have been quantitatively analyzed based on NASA-TLX(Task Load Index).

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An Investigation of Human Error Analysis Techniques in Various Industries with Implications for the Korean Railway Industry (인적오류 분석기법의 국내외 활용 현황 및 국내 철도 산업에의 적용 방안)

  • Baek, Dong-Hyun;Yoon, Wan-Chul;Kim, Dong-San
    • Journal of the Korean Society for Railway
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    • v.10 no.1 s.38
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    • pp.7-15
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    • 2007
  • Since human errors are being recognized as one of the primary issues in railway safety, there is a definite need for human error analysis techniques that can identify the types of errors and their causes and derive effective countermeasures to help reduce their future probability. But, for some reasons, there are not yet systematic procedures or techniques for analyzing human errors in the Korean railway industry. This paper introduces several techniques that have been developed and utilized for analyzing human errors in Korean and overseas nuclear power aviation railway, offshore oil industry, etc., and summarizes the strengths and weaknesses of each technique. Based on the Investigation of the techniques, the paper also discusses the implications for the development of a human error analysis system for the Korean railway industry.

A Computer Aided Drawing Check System (Global Dimension Check) (컴퓨터 지원에 의한 설계도면 검증시스템)

  • ;Ono, T.;Tsujio, S.
    • 제어로봇시스템학회:학술대회논문집
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    • 1992.10a
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    • pp.1102-1107
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    • 1992
  • Existing CAD systems do nto provide the advanced function for systematic checking of design and drafting errors in mechanical drawings. This paper describes a method for sytematic checking of global parts in mechanical drawings. The checking items are deficiency and redundancy of dimensions, input-errors in dimension figures and symbols, etc. Checking for deficiency and redundancy of global dimensions has been performed applying Graph Theory. This system has been applied to several examples and we have confirmed the feasibility of this checing method.

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Identification of Implementation Strategy by Practical Interpretations of Significance Level, Significance Probability, and Known Parameters in Statistical Inferences (통계적 추론에서 유의수준, 유의확률과 모수기지의 실무적 해석에 의한 적용방안)

  • Choe, Seong-Un
    • Proceedings of the Safety Management and Science Conference
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    • 2012.04a
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    • pp.75-80
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    • 2012
  • The research presents a guideline for quality practitioners to provide a full comprehension of differences in theoretical and practical interpretations of assumed sampling errors of and significance probability of calculated p-value. Besides, the study recommends the use of statistical inferences methods with known parameters to identify the improvement effects. In practice, the quality practitioners obtain the known parameters through systematic quality Database (DB) activities.

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Comparison of Misalignment and Retardation Errors of Dual Rotating Quarter-Wave Plates in Muller-Matrix Ellipsometry (타원편광 분석기에서 정렬오차와 사분파장판의 지연오차로 인한 뮬러 매트릭스 오차 분석)

  • Cheong, Hai Du;Kim, Dukhyeon
    • Korean Journal of Optics and Photonics
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    • v.25 no.5
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    • pp.262-272
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    • 2014
  • Using an ellipsometer with dual rotating quarter-wave plates, we have analyzed the relationship between Fourier coefficients and Mueller matrices in the cases of an error-free optical system and of five systematic errors (alignment errors and retardation errors in the quarter-wave plates, and alignment error in the analyzer). In the case with five systematic errors, simulation results show that retardation errors cause more error in the diagonal elements of the Mueller matrix than do alignment errors. We have found that errors in the Mueller matrix caused by initial misalignment of the dual quarter-wave plates were the same. We have chosen the rotation rates of two quarter-wave plates such that the rotational frequencies ${\omega}_1$ and ${\omega}_2$ differ by a factor of 5, i.e. ${\omega}_2=5{\omega}_1$. The simulation results show 0.18% relative error in the diagonal elements ($m_{22}$ and $m_{33}$) and 200% relative error in the off-diagonal elements ($m_{23}$ and $m_{32}$), when we compare errors caused by misalignment of the analyzer to those caused by initial misalignment of the quarter-wave plates. We can use these results in measuring accurate Mueller matrices of optical materials.